Hermetic-type compressors for use in refrigeration apparatuses and the like are strongly requested to have improved refrigeration capability and to reduce noise.
As conventional technologies for improving refrigeration capability, the hermetic-type compressors have been disclosed in Japanese Laid-open Patent Application No. Sho 57-122192 and No. Hei 6-50262, for example. In these conventional technologies, pressure in a cylinder at the time when the suction of refrigerant gas is completed is raised higher than the pressure on the low-pressure side of a refrigeration cycle, whereby the density of refrigerant gas to be sucked into the cylinder is raised so as to further improve refrigeration capability.
In addition, as a conventional technology for reducing noise, a hermetic-type compressor has been disclosed in Japanese Laid-open Patent Application No. Hei 6-74154, for example. In this hermetic-type compressor, its suction portion for sucking refrigerant gas into its cylinder has been improved in order to prevent the generation of resonance sound which generates in its enclosed container during suction in a compression stroke.
An example of conventional hermetic-type compressors intended to reduce noise is described below referring to the drawings.
FIG. 67 is a vertical sectional view showing a conventional hermetic-type compressor, and FIG. 68 is a plan sectional view showing the conventional hermetic-type compressor shown in FIG. 67.
In FIGS. 67 and 68, a hermetic-type compressor 1 has an enclosed container 2 comprising a lower shell 3 and an upper shell 4. An electric compression element 5 disposed vertically in the enclosed container 2 is elastically supported in the enclosed container 2 by coil springs 8 so that a mechanical portion 6 is disposed in the upper portion and so that a motor portion 7 is disposed in the lower portion.
The mechanical portion 6 comprises a cylinder 10 integrally provided with a block 9, a piston 11, a crankshaft 12, a connecting rod 13, a bearing 14, a cylinder head 80 and the like. The motor portion 7 comprises a rotor 15 secured by shrinkage fit to the crankshaft 12 and a stator 16. The stator 16 is secured to the block 9 using screws. Lubricant 17 is stored at the bottom of the enclosed container 2.
Mark a in FIG. 68 represents the minimum distance between the inner walls of the enclosed container 2 along the center of gravity of a plane having nearly the maximum cross-sectional area on a horizontal section of the enclosed container 2. In other words, the distance a is the maximum distance in a direction perpendicular to the reciprocating direction of the piston 11 and the axial direction of the crankshaft 12. Mark b represents the distance between the inner walls of the enclosed container 2 in a direction nearly perpendicular to the line segment of the above-mentioned distance a on the same horizontal plane. That is, the distance b is the maximum distance between the inner walls of the enclosed container 2 in the reciprocating direction of the piston 11. Mark c represents the maximum distance from the upper inner wall surface of the enclosed container 2 to the surface of the lubricant 17 in the axial direction of the crankshaft 12.
In a suction pipe 18 for sucking refrigerant gas in the enclosed container 2, its one end is secured to the block 9, and the other end passes through the center of the line indicated by the distance a and is disposed on a plane orthogonal to the line. This other end is disposed in the space inside the enclosed container 2 as an opening end 18a, and communicates with the space inside the cylinder 10.
The operation of the conventional hermetic-type compressor having the above-mentioned configuration is described below.
Refrigerant gas circulated from a system such as a refrigeration apparatus is relieved once in the space inside the enclosed container 2, sucked into the cylinder 10 via the suction pipe 18 secured to the block 9, and compressed by the piston 11. At this time, the refrigerant gas is sucked into the cylinder 10 by one half rotation of the crankshaft 12, and then compressed by the other half rotation.
Since the refrigerant gas is not sucked continuously into the cylinder 10 as described above, the pressure pulsation of the refrigerant gas occurs in the suction pipe 18. Therefore, the pressure pulsation vibrates the space inside the enclosed container 2, and resonance modes are generated in the reciprocating direction of the piston 11, in a direction perpendicular to the reciprocating direction on a horizontal plane including the reciprocating direction of the piston 11, and in the axial direction of the crankshaft 12.
However, the opening end 18a of the suction pipe 18 in the space inside the enclosed container 2 is disposed on a plane passing through the center of the line indicated by the distance a and being orthogonal to the line, that is, on a plane including the position of a node of the resonance mode generated in the direction perpendicular to the reciprocating direction on the horizontal plane including the reciprocating direction of the piston 11.
Therefore, in the conventional hermetic-type compressor shown in FIGS. 67 and 68, the pressure pulsation vibrates the node of the resonance mode. As a result, in the conventional hermetic-type compressor, no resonance mode is caused, the generation of resonance sound is prevented, and noise due to resonance sound is prevented.
In addition, when the resonance mode at a resonance frequency causing a problem occurs in the reciprocating direction of the piston 11 of the enclosed container 2, the opening end 18a of the suction pipe 18 in the space inside the enclosed container 2 is disposed at the following position. Referring to FIG. 68, on the same horizontal plane of a line segment A indicated by the distance a along the center of gravity on a horizontal section, in a line segment B indicated by the distance b between the inner walls of the enclosed container 2 and being nearly orthogonal to the line segment A, the opening end 18a is disposed on a plane passing through the center of the line segment B and being orthogonal to the line segment B. Therefore, the pressure pulsation vibrates on the node of the resonance mode. Consequently, no resonance mode is caused, whereby the generation of resonance sound can be prevented, and noise due to resonance sound can be prevented in the hermetic-type compressor.
Furthermore, when the resonance mode at the resonance frequency causing a problem is present in the axial direction of the crankshaft 12 of the enclosed container 2, the opening end 18a of the suction pipe 18 in the space inside the enclosed container 2 is disposed at the following position. In other words, with respect to a line segment C indicated by a distance c (FIG. 67) which is the maximum distance between the upper inner wall surface of the enclosed container 2 in the vertical direction and the surface of the lubricant 17, the opening end is disposed on a plane passing through the center of the line segment C and being orthogonal to the line segment C. Therefore, the pressure pulsation vibrates on the node of the resonance mode, the generation of resonance sound can be prevented, and noise due to resonance sound can be prevented in the hermetic-type compressor.
Next, an example of the conventional hermetic-type compressor intended for improved refrigeration capability is described below referring to the drawings.
FIG. 69 is a vertical sectional view showing a conventional hermetic-type compressor intended for improved refrigerant capability. FIG. 70 is a plan sectional view showing the conventional hermetic-type compressor of FIG. 69. FIG. 71 is a sectional view showing the main portion of the compressor taken on line A--A of FIG. 69. FIG. 72 is an explanatory view showing the behavior of refrigerant gas.
In FIGS. 69, 70, 71 and 72, a valve plate 19 has a suction hole 19a and is disposed at the end surface of the cylinder 10. The suction hole 19a (FIGS. 70 and 71) communicates with a suction pipe 21 and the interior of the cylinder 10. A suction valve 20 shown in FIG. 71 opens and closes the suction hole 19a of the valve plate 19. One end 21a of the suction pipe 21 is open into the space inside the enclosed container 2, and its other end 21b is directly connected to the valve plate 19.
On the other hand, in the conventional rotary compressor intended for improved refrigeration capability and disclosed in Japanese Laid-open Patent Application No. Sho 57-122192, when a suction stroke period is T (sec), and the velocity of sound in the suction condition of refrigerant gas to be sucked is a (m/sec), the length L (m) of the suction pipe 21 is represented by: EQU (T.times.a/4-0.2).+-.0.1=L
Next, the operation of the conventional hermetic-type compressor having the above-mentioned configuration is described below.
In FIG. 72, in the case of refrigerant gas, at the start of a suction stroke (at time of (a) in FIG. 72), the suction hole 19a of the valve plate 19 is clogged. Therefore, the flow of the refrigerant gas stops.
Next, the piston 11 moves to the right, and the volume inside the cylinder 10 increases abruptly. Therefore, a pressure difference generates between the space inside the cylinder 10 and the space inside the enclosed container 2, and the refrigerant gas begins to flow rightward (toward the cylinder 10) inside the suction pipe 21. At the same time, a pressure wave Wa is generated in the cylinder 10 because the volume inside the cylinder 10 increases abruptly. The pressure wave Wa inside the cylinder 10 passes through the suction hole 19a used as an opening, and propagates though the interior of the suction pipe 21 in the direction opposite to the flow of the refrigerant gas toward the space inside the enclosed container 2 (at time of (b) in FIG. 72).
The pressure wave Wa reached the space inside the enclosed container 2 becomes a reflected wave Wb having been inverted in the space inside the enclosed container 2 in which the refrigerant gas is in a stagnate condition. This reflected wave Wb propagates through the interior of the suction pipe 21 in the same direction as the flow of the refrigerant gas (at time of (c) in FIG. 72).
In other words, the pressure wave Wa generated in the cylinder 10 passes through the suction hole 19a of the valve plate 19, and propagates in the direction opposite to the flow of refrigerant gas. Then, the pressure wave Wa becomes the reflected wave Wb having an inverse phase in the space inside the enclosed container 2, and propagates in the same direction as the flow of the refrigerant gas, and returns to the suction hole 19a of the valve plate 19.
By aligning the time when the reflected wave Wb reaches the suction hole 19a with the time when the volume inside the cylinder 10 becomes maximum (suction completion time), the pressure energy of the reflected wave Wb can be added to the refrigerant gas at the suction completion time, and the suction pressure of the refrigerant gas is raised.
As a result, refrigerant gas having a higher density is charged into the cylinder 10, the discharge amount of refrigerant per a compression stroke increases, the circulation amount of refrigerant increases, and the refrigeration capability of the hermetic-type compressor is improved.
However, in the above-mentioned conventional hermetic-type compressor, when the velocity of sound propagating through refrigerant gas (hereinafter referred to as the velocity of sound in refrigerant gas) is changed by a change in the temperature of the refrigerant gas due to a change in outside-air temperature, the position of the node of the resonance mode at the resonance frequency is changed, and the generation of resonance sound may not be prevented.
In addition, shock sound is generated by a pressure wave generated by the suction pipe, and noise may be generated.
Furthermore, when the velocity of sound is changed by a change in the temperature of the refrigerant gas due to a change in outside-air temperature, the wavelengths of the pressure wave and the reflected wave are changed depending on the velocity of sound. Therefore, the timing of adding the pressure energy of the reflected wave at the suction completion time generates an error, and the rising ratio of the suction pressure lowers.
Therefore, it becomes difficult to charge refrigerant gas having a higher density into the cylinder, the discharge amount of refrigerant gas per a compression stroke decreases, and refrigeration capability may lower.
Moreover, a method of improving refrigeration capability by always increasing the circulation amount of refrigerant gas regardless of a change in outside-air temperature can be devised. In this case, however, a room is often closed in winter or during cold days when outside-air temperature is low, and noise due to shock sound may become more annoying than that in summer.
The present invention is intended to solve the above-mentioned problems, and aims to provide a hermetic-type compressor having high refrigeration capability, low suction loss of refrigerant gas and high refrigeration efficiency.
Accordingly, the hermetic-type compressor of the present invention is intended to attain the above-mentioned objects and also attain the following technological advantages by using various embodiments described later.
In embodiment 1 of the present invention described later, even when a node of a resonance mode at a resonance frequency is changed because the velocity of sound in refrigerant gas is changed by a change in the temperature of the refrigerant gas, the opening end of the suction pipe is adjusted so as to be always positioned at the node of the resonance mode. Therefore, a hermetic-type compressor, wherein the generation of resonance sound is prevented, and low noise is attained, is provided.
In embodiment 2 of the present invention described later, the opening end of the suction pipe is adapted to become a node of a resonance mode, whereby the generation of shock sound generated by a pressure wave at the suction pipe can be prevented significantly. Therefore, a hermetic-type compressor, wherein noise is reduced, refrigeration capability is high, the suction loss of refrigerant gas is low and efficiency is high, can be provided.
In embodiment 3 of the present invention described later, the length of a suction passage in the suction pipe is changed. Therefore, even when the velocity of sound in refrigerant gas is changed by a change in the temperature of the refrigerant gas due to a change in outside-air temperature, the time when a reflected wave reaches the suction hole can be aligned with the time when the volume inside the cylinder becomes maximum (suction completion time). Therefore, the pressure energy of the reflected wave is added to the refrigerant gas at the suction completion time, and the suction pressure of the refrigerant gas is raised.
Therefore, the suction pressure rises at all times, the discharge amount of refrigerant gas per a compression stroke increases, the circulation amount of refrigerant gas increases, refrigeration capability is improved, and the suction loss of refrigerant gas is reduced. Consequently, a hermetic-type compressor having high efficiency can be obtained.
In embodiment 4 of the present invention described later, the inner cross-sectional area of the suction pipe is changed. Therefore, even when the velocity of sound in refrigerant gas is changed by a change in the temperature of the refrigerant gas due to a change in outside-air temperature, the time when a reflected wave reaches the suction hole can be aligned with the time when the volume inside the cylinder becomes maximum (suction completion time). Therefore, the pressure energy of the reflected wave can be added at the suction completion time, and the suction pressure of the refrigerant gas is raised.
Therefore, the suction pressure rises at all times, the discharge amount of refrigerant per a compression stroke increases, the circulation amount of refrigerant increases, refrigeration capability is improved, and the suction loss of refrigerant gas is reduced. As a result, a hermetic-type compressor having high efficiency can be obtained.
In comparison with the time when outside-air temperature is high, at the time when outside-air temperature is low, and refrigeration capability is not required to be improved greatly, the inner cross-sectional area of the suction pipe is decreased; the inner cross-sectional area of the suction pips is reduced as outside-air temperature lowers. Consequently, a hermetic-type compressor capable of significantly reducing noise can be obtained.
In the conventional configuration, the rotation position of the crankshaft when a reflected wave returns to the suction hole was not always proper depending on the length of the suction pipe 21, operation frequency or the velocity of sound in refrigerant gas. Therefore, the improvement ratio of refrigeration capability may be low.
Thus, in embodiment 5 of the present invention described later, the length and the like of the suction pipe are adjusted so that the rotation position (crank angle) of the crank shaft, wherein a reflected wave returns to the suction hole, is optimal, whereby a hermetic-type compressor capable of obtaining the improvement effect of maximum refrigeration capability can be obtained.
The conventional configuration was intended to always improve refrigeration capability even when outside-air temperature was high and even when it was low. Therefore, at low outside-air temperature at which no high refrigeration capability is required, more than necessary refrigeration capability is supplied, and the overall efficiency of a refrigeration system including the hermetic-type compressor is lowered; as a result, a disadvantage arises, that is, overall electric power consumption is apt to increase.
In embodiment 6 of the present invention described later, electric power consumption is decreased by not allowing the improvement effect of refrigeration capability to be obtained at low outside-air temperature at which no high refrigeration capability is required; on the other hand, at high outside-air temperature at which high refrigeration capability is required, the embodiment is configured so that the improvement effect of refrigeration capability can be obtained in a conventional way. Consequently, a hermetic-type compressor having low overall electric power consumption can be obtained by controlling refrigeration capability as described above.
In the conventional configuration, resonance sound is generated when the resonance frequency of refrigerant gas in the enclosed container is close to an integral multiple of the rotation number of the crankshaft, and the refrigerant gas in the enclosed container resonates. Therefore, when the pressure wave is reflected at the opening end of the suction pipe, the refrigerant gas in the enclosed container resonates. Due to its influence, the pressure amplitude of the reflected wave decreases, the rising ratio of suction pressure lowers, and a disadvantage arises, that is, the improvement effect of refrigeration capability is apt to become low.
In embodiment 7 of the present invention described later, the resonance frequency of refrigerant gas in the enclosed container is not close to an integral multiple of the rotation number of the crankshaft. Therefore, resonance sound is prevented from generating, and pressure amplitude is also prevented from decreasing when a pressure wave is reflected at the opening of the suction pipe. Consequently, a hermetic-type compressor, wherein suction pressure can be raised at all times, and the improvement effect of refrigeration capability can be obtained, can be obtained.
In embodiment 8 of the present invention described later, the force for vibrating refrigerant gas in the enclosed container is reduced by decreasing the pulsation of refrigerant gas to be sucked, and resonance sound is always diminished regardless of the resonance frequency of the refrigerant gas in the enclosed container. In addition, the pressure amplitude obtained when a pressure wave is reflected at the opening portion of the suction pipe is prevented at all times regardless of the resonance frequency of the refrigerant gas in the enclosed container. Consequently, a hermetic-type compressor, wherein suction pressure is raised at all times regardless of any change in the shape of the enclosed container, operation conditions and the like, and the improvement effect of refrigeration capability is obtained, can be obtained.
In the above-mentioned conventional configuration shown in FIG. 69, the suction pipe 21 makes contact with the cylinder head 80 and the valve plate 19. Therefore, the temperatures of the cylinder head 80 and the like rise significantly with the passage of time after start, and by following the temperature rise, the temperature of the suction pipe 21 also rises. As a result, the temperature of the refrigerant gas in the suction pipe 21 rises, the velocity of sound in the refrigerant gas changes, and the timing when the reflected wave reaches the suction hole 19a deviates. Consequently, in the conventional hermetic-type compressor, a stable suction pressure rising effect may not be obtained.
Thus, in embodiment 9 of the present invention described later, even when the temperature of the cylinder head or the like changes significantly, the change in the temperature of the suction pipe is decreased. Therefore, the change in the velocity of sound in refrigerant gas can be decreased, and a stable suction pressure rising effect is produced. Therefore, a hermetic-type compressor having stable and high refrigeration capability without being affected by the passage of time after start can be obtained.
In the conventional configuration shown in FIG. 69, since the opening end 21a of the suction pipe 21 is disposed in the enclosed container 2, high-temperature refrigerant gas having a low density is sucked into the suction pipe 21. Therefore, the velocity of sound in refrigerant gas increases, an influence of compressibility reduces, and the generation of the pressure wave becomes weak. As a result, in the conventional hermetic-type compressor, suction pressure may decrease.
If the opening end 21a of the suction pipe 21 is communicated with the opening end of the second suction pipe in the enclosed container 2 so that low-temperature refrigerant gas can be sucked into the cylinder 10, no reflected wave is generated, and the suction pressure may not be raised.
In embodiment 10 of the present invention described later, a large pressure wave is generated, and the effect of raising suction pressure increases, and low-temperature refrigerant gas is sucked into the cylinder. Therefore, the improvement effect of the circulation amount of refrigerant due to the low-temperature refrigerant gas is added, the improvement effect of refrigeration capability is increased significantly, whereby a hermetic-type compressor having high refrigeration capability and attaining low noise can be obtained.
In the conventional configuration shown in FIG. 69, when the sound of velocity in refrigerant gas is changed depending on operation conditions and the like, if the length of the suction pipe 21 is constant, the time required when the reflected wave reaches the suction hole 19a of the valve plate 19 changes. Therefore, suction timing to the cylinder 10 deviates, whereby the suction pressure rising effect significantly decreases depending on operation conditions, and refrigeration capability may become insufficient.
Thus, in embodiment 11 of the present invention described later, suction pressure is raised at all times regardless of a change in operation conditions, and stable and high refrigeration capability is provided.
In the conventional configuration shown in FIG. 69, since the suction pipe 21 always communicates with the suction hole 19a, the suction pressure rising effect occurs at start. Therefore, start torque becomes high; in a high pressure condition such as in a condition wherein outside-air temperature is high, improper start may occur due to insufficient torque.
Thus, in embodiment 12 of the present invention described later, the suction pressure rising effect is lessened, and start torque is lowered so as to prevent improper start. Therefore, a hermetic-type compressor having improved reliability and high refrigeration capability due to the suction pressure rising effect during stable operation can be obtained.
In the conventional configuration shown in FIG. 69, when refrigerant gas is heated in the space inside the enclosed container 2, and the density of refrigerant gas to be charged into the cylinder 10 is lowered, the circulation amount of refrigerant gas decreases, and refrigeration capability may be lowered.
Thus, in embodiment 13 of the present invention described later, the opening end of the first suction pipe, which is used as a suction passage, in the enclosed container is disposed so that it becomes a node of a resonance mode. In addition, the opening end of the second suction pipe in the enclosed container is provided near the opening end of the suction passage. As a result, resonance is prevented from generating in the enclosed container. Therefore, a hermetic-type compressor attaining low noise and improving refrigeration capability is provided.
In the conventional configuration shown in FIG. 69, shock sound is generated by a pressure wave generated from the suction pipe 21, and noise is generated; in addition, refrigerant gas is heated in the space inside the enclosed container 2, and the density of refrigerant gas to be charged into the cylinder 10 is lowered. Therefore, in the conventional hermetic-type compressor, the circulation amount of refrigerant gas decreases, and refrigeration capability may be lowered.
Thus, in embodiment 14 of the present invention described later, the opening end of the first suction pipe, which is used as a suction passage, in the enclosed container is disposed so that it becomes a node of a resonance mode. In addition, the opening end of the second suction pipe in the enclosed container is provided near the opening end of the suction passage. Therefore, the generation of shock sound due to the pressure wave in the suction passage is reduced significantly, whereby a hermetic-type compressor featuring low noise, refrigerant gas having a high density and significantly improved refrigeration capability can be obtained.
In the conventional configuration, since a long suction passage is provided in the enclosed container having a limited space, the structure of the suction passage is complicated, and has a plurality of bent portions having different curvatures. Therefore, the amplitude of pressure decreases at the bent portions having different curvatures, when the pressure wave Wa and the reflected wave Wb propagate through the suction passage. In addition, when the reflected wave Wb returns to the suction hole of the valve plate, the pressure amplitude of the reflected wave Wb diminishes, whereby in the conventional hermetic-type compressor, the improvement effect of high refrigeration capability may not be obtained.
Thus, in embodiment 15 of the present invention described later, the attenuation of the pressure amplitudes of the pressure wave Wa and the reflected wave Wb are decreased, and suction pressure is raised. Therefore, a hermetic-type compressor having highly improved refrigeration capability can be obtained.
In the conventional configuration, the suction passage receives heat from high-temperature refrigerant gas in the enclosed container, the temperature of the suction passage rises, and the temperature of the suction gas in the suction passage rises. Therefore, the density of refrigerant gas to be sucked is lowered, and the circulation amount of refrigerant is apt to decrease.
Thus, in embodiment 16 of the present invention described later, the amount of heat received from high-temperature refrigerant gas in the enclosed container by the suction passage is lessened. Therefore, the temperature rise of the suction passage is reduced, whereby the temperature rise of the refrigerant gas in the suction passage is reduced. Consequently, a hermetic-type compressor capable of obtaining a large circulation amount of refrigerant can be obtained.
In addition, in embodiment 16, the temperature of refrigerant gas to be sucked is low, and refrigerant gas having a high density is sucked into the suction passage. Therefore, the velocity of sound in the refrigerant gas is lowered, whereby the compressibility of refrigerant gas increases. Consequently, a large pressure wave generates, and a hermetic-type compressor having improved high refrigeration capability can be obtained.
In the conventional configuration, since the opening end of the suction passage is open into the enclosed container, when the pressure wave is reflected at the opening end of the suction passage, the refrigerant gas in the enclosed container is vibrated, and resonance sound may generate.
Thus, in embodiment 17 of the present invention described later, the pulsation of suction gas is diminished, and the force for vibrating the refrigerant gas in the enclosed container is weakened. By this reason, the hermetic-type compressor can reduce resonance sound can be diminished regardless of the resonance frequency of the refrigerant gas in the enclosed container.
In embodiment 17, regardless of the resonance frequency of the refrigerant gas in the enclosed container, the attenuation of the pressure amplitude at the time when a pressure wave is reflected at the opening end of the suction passage can be prevented at all times. Therefore, regardless of any change in the shape of the enclosed container, operation conditions and the like, the suction pressure of the refrigerant gas rises at all times, whereby the hermetic-type compressor can obtain an improvement in stable and high refrigeration capability.
Furthermore, in embodiment 17, the temperature distribution of the suction passage is made uniform, and the change in the velocity of sound in the refrigerant gas is decreased. Therefore, in the hermetic-type compressor, the attenuation of the pressure wave can be decreased, and stable suction pressure rising can be obtained. Therefore, a hermetic-type compressor capable of obtaining an improvement in stable refrigeration capability can be obtained.
In the conventional configuration, even when high refrigeration capability is not required, for example during ordinary operation of the hermetic-type compressor, refrigeration capability increases, and motor input also increases accordingly, and then overall electric power consumption may increase.
Thus, embodiment 18 of the present invention described later is configured so that a supercharging effect can be obtained only at high outside-air temperature or at a high load wherein a high load is applied to the electric compression element. Therefore, a hermetic-type compressor requiring less electric power consumption can be obtained.
In the conventional configuration, the refrigerant gas in the suction passage is heated in the space inside the enclosed container, and the density of refrigerant gas to be charged into the cylinder is lowered. Therefore, in the conventional hermetic-type compressor, the circulation amount of refrigerant decreases, and refrigeration capability may lower.
Thus, embodiment 19 of the present invention described later is configured so that a supercharging effect can be obtained only at high outside-air temperature or at a high load wherein a high load is applied to the electric compression element. Therefore, electric power consumption is reduced on the whole. Further, the opening end of the first suction pipe in the enclosed container is provided near the opening end of the second suction pipe in the enclosed container, whereby the density of refrigerant gas to be sucked into the cylinder is raised, and a hermetic-type compressor having high efficiency can be obtained.
In the conventional configuration, the follow-up performance of the valve mechanism causes a problem, and refrigeration capability in proportion to an increase in rotation number may not be obtained particularly at a high rotation region.
Thus, in embodiment 20 of the present invention described later, in addition to rotation number control, supercharging is performed particularly in a high rotation range so as to obtain refrigeration capability higher than that proportional to rotation number. Therefore, the hermetic-type compressor of embodiment 20 can obtain refrigeration capability required depending on outside-air temperature or a load, and electric power consumption can be decreased.
In the conventional configuration shown in FIG. 69, the suction pipe 21 used as the suction passage is nearly directly connected to the valve plate 19. Therefore, in the conventional hermetic-type compressor, noise generated depending on the pulsation or the like of suction gas near the suction hole 19a propagates through the suction passage without being attenuated significantly, and noise propagating outside the enclosed container 2 may increase eventually.
Thus, in embodiment 21 of the present invention described later, without reducing refrigeration capability, noise generated due to the pulsation or the like of refrigerant gas to be sucked is diminished. Therefore, the hermetic-type compressor of embodiment 21 becomes a low noise compressor.
In the conventional configuration, as shown by Wb in FIG. 72, when the reflected wave returns into the cylinder 10, the suction lead 20 is disposed at an angle nearly perpendicular to the advance direction of the reflected wave. Therefore, the reflected wave is mostly reflected at the angle nearly perpendicular to the suction lead. Consequently, the pressure energy of the reflected wave does not effectively propagate into the cylinder 10, a supercharging effect to refrigerant gas by the reflected wave cannot be obtained sufficiently, and the improvement of refrigerant capability may not be obtained sufficiently.
Thus, embodiment 22 of the present invention described later is configured so that when the reflected wave returns into a cylinder, the reflected wave is hardly reflected by the suction lead, and so that the pressure energy of the reflected wave effectively enters the cylinder. Therefore, the hermetic-type compressor of embodiment 22 has high refrigeration capability.
In the above-mentioned conventional configuration, high refrigeration capability can be obtained at all times even when outside-air temperature is high and even when it is low. Therefore, in the conventional hermetic-type compressor, at low outside-air temperature at which no high refrigeration capability is required, more than necessary refrigeration capability is supplied, and the overall efficiency of the refrigeration system including the hermetic-type compressor is lowered. Thus, as a result, the overall electric power consumption may increase.
Thus, embodiments 23 and 24 of the present invention described later are configured so that high refrigeration capability cannot be obtained at low outside-air temperature at which high refrigeration capability is not required, whereby electric power consumption is reduced; on the other hand, they are configured so that refrigeration capability as high as a conventional value can be obtained at high outside-air temperature at which high refrigeration capability is required. Therefore, by controlling refrigeration capability, a hermetic-type compressor having low overall electric power consumption can be obtained.